The investigators conduct a randomized, double-blind, placebo-controlled study to investigate the effects of Skate Skin extract on cognitive function in adults with subjective memory impairment for 12 weeks.

Previous animal studies have indicated that Skate Skin extract may have the ability to improve cognitive function. Therefore, the investigators conduct a randomized, double-blind, placebo-controlled study to investigate the effects of Skate Skin extract on cognitive function in adults with subjective memory impairment for 12 weeks; the safety of the compound are also evaluate. The Investigators examine chemical and metabolic parameters, and cognitive function at baseline, as well as after 6 and 12 weeks of intervention. One hundred adults were administered either 500 mg of Skate Skin extract or a placebo each day for 12 weeks;

Inclusion Criteria:

• Global Deterioration Scale (GDS) 2 or 3

Exclusion Criteria:

• Abnormal liver or renal function (i.e., serum aminotransferase activity > 3 times of upper limit of reference range and serum creatinine concentrations > 1.2 mg/dL)
• Diabetes (diagnosed clinically or fasting glucose level > 126 mg/dL)
• History of viral hepatitis or cancer
• Uncontrolled hypertension
• History of serious cardiac disease such as angina or myocardial infarction
• History of gastrectomy
• History of medication for psychiatric disease
• Administration of oriental medicine including herbs within the past 4 weeks